This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Aim: Study the hypothesis of vascular normalization as a result of Avastin treatment. We will use both dynamic micro-CT with a Isovue 370 to visualize perfusion and static micro-CT with a liposomal contrast agent to visualize permeability in tumors. 12 animals with viable tumors will be transfered from Piedmont Research Center to Duke on 1-5-10. 6 mice will be treated with Avastin and 6 mice will be controls. Treatment involves 5mg/kg of Avastin given IP biweekly, and will take place on: Thursdays and Mondays starting on Thursday January 7th. The first imaging day will be Friday January 8th. 4 treatment groups: 1) Control Liposome, 3 animals (CL) 2) Control Perfusion, 3 animals (CP) 3) Treated Liposome, 3 animals ( TL) 4) Treated Perfusion, 3 animals (TP) The groups CL and TL will be injected via tail vein with liposomal contrast ( 0.3 ml/25g mouse) on Mondays and static micro-CT imaging will take place on Mondays (0 hours) and Wednesdays (48hours) every week. The groups CP and TP will be imaged once per week on Fridays using dynamic micro-CT to compare perfusion. For these stusdies we will use a tail vein catheter to deliver Isovue 370 in a dose of 0.5ml/25 g mouse). Animals will be recovered after each imaging session. We expect that untreated mice (CL, CP) will reach the end point when they will need to be sacrificed in about 17 days with Day 0 starting on January 5th. The treated animals (TL, TP) will reach the endpoint in about 36 days. Therefore, imaging the 6 animals in groups (CP,CP) will take place for only 2 weeks. For untreated animals the imaging could last up to 5 weeks.